Problem: Given a string of length n s = s1, s2,…, sn and m queries. Each query qk (1 ≤ k ≤ m) is one of four types, "L ++", "L-", "R ++", "R-", and l [for the kth query qk. k] and r [k] are defined below.

* L ++: l [k] = l [k-1] + 1, r [k] = r [k-1]

* L-: l [k] = l [k-1] -1, r [k] = r [k-1]

* R ++: l [k] = l [k-1], r [k] = r [k-1] +1

* R-: l [k] = l [k-1], r [k] = r [k-1] -1




However, l [0] = r [0] = 1.

At this time, how many kinds of character strings are created for m substrings sl [k], sl [k] + 1,…, sr [k] -1, sr [k] (1 ≤ k ≤ m). Answer if you can.

Constraints

* The string s consists of a lowercase alphabet

* 1 ≤ n ≤ 3 x 105

* 1 ≤ m ≤ 3 × 105

* qk (1 ≤ k ≤ m) is one of "L ++", "L-", "R ++", "R-"

* 1 ≤ l [k] ≤ r [k] ≤ n (1 ≤ k ≤ m)

Input

Input is given in the following format

> n m
> s
> q1
> q2
>…
> qm
>

Output

Output the solution of the problem on one line

Examples

Input

5 4
abcde
R++
R++
L++
L--


Output

3


Input

4 6
abab
R++
L++
R++
L++
R++
L++


Output

4


Input

10 13
aacacbabac
R++
R++
L++
R++
R++
L++
L++
R++
R++
L--
L--
R--
R--


Output

11

Solution (in JAVA):

Solution:
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.HashSet;
import java.util.InputMismatchException;
import java.util.NoSuchElementException;

public class Main {

	public static void main(String[] args) {
		IO io = new IO();
		int n = io.nextInt();
		int m = io.nextInt();
		char[] s = io.nextCharArray(n);
		HashSet<LongArray> hs = new HashSet<>();
		RollingHash rh = new RollingHash(s, new long[] {1000000007,1000000009,1000000021});
		rh.init(0, 0);
		for(int i=0;i<m;i++) {
			String q = io.next();
			if (q.equals("L++")) {
				rh.leftPlus();
			}else if(q.equals("L--")) {
				rh.leftMinus();
			}else if(q.equals("R++")) {
				rh.rightPlus();
			}else{
				rh.rightMinus();
			}
			hs.add(new LongArray(Arrays.copyOf(rh.h, rh.h.length)));
		}
		System.out.println(hs.size());
	}

}
class RollingHash {
	char[] s;
	int n;
	long[] base;
	long[] mod;
	long[] inv;
	long[] h;
	int l, r;
	public RollingHash(char[] s,long[] mod) {
		this.s = s;
		this.n = mod.length;
		this.mod = mod;
		base = new long[n];
		inv = new long[n];
		for(int i=0;i<n;i++) {
			base[i] = (int) ((Math.random() * 0.5 + 0.25) * mod[i]);
			inv[i] = inverse(base[i], mod[i]);
		}
		h = new long[n];
	}
	public void init(int l,int r) {
		for(int i=r;i>=l;i--) {
			for(int j=0;j<n;j++) {
				h[j] = (h[j] * base[j] + s[i]) % mod[j];
			}
		}
	}
	public void leftMinus() {
		for(int i=0;i<n;i++) {
			h[i] = (h[i] * base[i] % mod[i] + s[l-1]) % mod[i];
		}
		l--;
	}
	public void leftPlus() {
		for(int i=0;i<n;i++) {
			h[i]= (h[i] + mod[i] - s[l]) * inv[i] % mod[i];
		}
		l++;
	}
	public void rightPlus() {
		for(int i=0;i<n;i++) {
			h[i] = (h[i] + s[r+1] * pow(base[i],r-l+1,mod[i]) % mod[i]) % mod[i];
		}
		r++;
	}
	public void rightMinus() {
		for(int i=0;i<n;i++) {
			h[i] = (h[i] + mod[i] - s[r] * pow(base[i],r-l,mod[i]) % mod[i]) % mod[i];
		
		}
		r--;
	}
	public static long pow(long a,long n,long mod) {
		long res = 1;
		while(n > 0) {
			if ((n & 1) > 0) {
				res = (res * a) % mod;
			}
			a = (a * a) % mod;
			n/=2;
		}
		return res;
	}
	public static long inverse(long a,long mod) {
		long b = mod, u = 1, v = 0;
		while(b > 0) {
			long temp;
			long t = a / b;
			a -= t * b;
			temp = a; a = b; b = temp;
			u -= t * v;
			temp = u; u = v; v = temp;
		}
		return (u % mod + mod) % mod;
	}
}
class LongArray {
	long[] h;
	public LongArray(long[] h) {
		this.h = h;
	}
	public boolean equals(Object o) {
		if (o instanceof LongArray) {
			return Arrays.equals(h, ((LongArray) o).h);
		}
		return super.equals(o);
	}
	public int hashCode() {
		return Long.hashCode(h[0]);
	}
	public String toString() {
		return Arrays.toString(h);
	}
	
}
class IO extends PrintWriter {
	private final InputStream in;
	private final byte[] buffer = new byte[1024];
	private int ptr = 0;
	private int buflen = 0;

	public IO() { this(System.in);}
	public IO(InputStream source) { super(System.out); this.in = source;}
	private boolean hasNextByte() {
		if (ptr < buflen) {
			return true;
		}else{
			ptr = 0;
			try {
				buflen = in.read(buffer);
			} catch (IOException e) {
				e.printStackTrace();
			}
			if (buflen <= 0) {
				return false;
			}
		}
		return true;
	}
	private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
	private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
	private static boolean isNewLine(int c) { return c == '\n' || c == '\r';}
	public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
	public boolean hasNextLine() { while(hasNextByte() && isNewLine(buffer[ptr])) ptr++; return hasNextByte();}
	public String next() {
		if (!hasNext()) {
			throw new NoSuchElementException();
		}
		StringBuilder sb = new StringBuilder();
		int b = readByte();
		while(isPrintableChar(b)) {
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	public char[] nextCharArray(int len) {
		if (!hasNext()) {
			throw new NoSuchElementException();
		}
		char[] s = new char[len];
		int i = 0;
		int b = readByte();
		while(isPrintableChar(b)) {
			if (i == len) {
				throw new InputMismatchException();
			}
			s[i++] = (char) b;
			b = readByte();
		}
		return s;
	}
	public String nextLine() {
		if (!hasNextLine()) {
			throw new NoSuchElementException();
		}
		StringBuilder sb = new StringBuilder();
		int b = readByte();
		while(!isNewLine(b)) {
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	public long nextLong() {
		if (!hasNext()) {
			throw new NoSuchElementException();
		}
		long n = 0;
		boolean minus = false;
		int b = readByte();
		if (b == '-') {
			minus = true;
			b = readByte();
		}
		if (b < '0' || '9' < b) {
			throw new NumberFormatException();
		}
		while(true){
			if ('0' <= b && b <= '9') {
				n *= 10;
				n += b - '0';
			}else if(b == -1 || !isPrintableChar(b)){
				return minus ? -n : n;
			}else{
				throw new NumberFormatException();
			}
			b = readByte();
		}
	}
	public int nextInt() {
		long nl = nextLong();
		if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) {
			throw new NumberFormatException();
		}
		return (int) nl;
	}
	public char nextChar() {
		if (!hasNext()) {
			throw new NoSuchElementException();
		}
		return (char) readByte();
	}
	public double nextDouble() { return Double.parseDouble(next());}
	public int[] nextIntArray(int n) { int[] a = new int[n]; for(int i=0;i<n;i++) a[i] = nextInt(); return a;}
	public long[] nextLongArray(int n) { long[] a = new long[n]; for(int i=0;i<n;i++) a[i] = nextLong(); return a;}
	public double[] nextDoubleArray(int n) { double[] a = new double[n]; for(int i=0;i<n;i++) a[i] = nextDouble(); return a;}
	public void nextIntArrays(int[]... a) { for(int i=0;i<a[0].length;i++) for(int j=0;j<a.length;j++) a[j][i] = nextInt();}
	public int[][] nextIntMatrix(int n,int m) { int[][] a = new int[n][]; for(int i=0;i<n;i++) a[i] = nextIntArray(m); return a;}
	public char[][] nextCharMap(int n,int m) { char[][] a = new char[n][]; for(int i=0;i<n;i++) a[i] = nextCharArray(m); return a;}
	public void close() { super.close(); try {in.close();} catch (IOException e) {}}
}